title: Numerical analysis of water and solute transport in variably-saturated fractured clayey till.
abstract: This study numerically investigates the influence of initial water content and rain intensities on the preferential migration of two fluorescent tracers, Acid Yellow 7 (AY7) and Sulforhodamine B (SB), through variably-saturated fractured clayey till. The simulations are based on the numerical model HydroGeoSphere, which solves 3D variably-saturated flow and solute transport in discretely-fractured porous media. Using detailed knowledge of the matrix, fracture, and biopore properties, the numerical model is calibrated and validated against experimental high-resolution tracer images/data collected under dry and wet soil conditions and for three different rain events. The model could reproduce reasonably well the observed preferential migration of AY7 and SB through the fractured till, although it did not capture the exact depth of migration and the negligible impact of the dead-end biopores in a near-saturated matrix. A sensitivity analysis suggests fast flow mechanisms and dynamic surface coating in the biopores, and the presence of a plough pan in the till.
authors.affiliation: The Geological Survey of Denmark and Greenland (GEUS), Copenhagen K, Denmark. aer@geus.dk
authors.forename: Annette E
authors.initials: AE
authors.lastname: Rosenbom
authors.forename: Rene
authors.initials: R
authors.lastname: Therrien
authors.forename: Jens Christian
authors.initials: JC
authors.lastname: Refsgaard
authors.forename: Karsten H
authors.initials: KH
authors.lastname: Jensen
authors.forename: Vibeke
authors.initials: V
authors.lastname: Ernstsen
authors.forename: Knud Erik S
authors.initials: KE
authors.lastname: Klint
mesh_terms: D000538:Aluminum Silicates; D002138:Calibration; D000077215:Clay; D008855:Microscopy, Electron, Scanning; D008962:Models, Theoretical; D016062:Porosity; D012680:Sensitivity and Specificity; D012996:Solutions; D014872:Water Movements
chemical_list: D000538:Aluminum Silicates; D012996:Solutions; D000077215:Clay